The present invention relates to clamping inserts for use with clamping devices for mounting derailleurs to bicycle frames, and more particularly, to a one-piece flexible clamping insert configured to make a derailleur clamping device adaptable for mounting to a variety of frames.
A typical bicycle derailleur, in particular a front derailleur, is mounted to a seat tube of the bicycle frame by a clamping device or simply a “clamp.” The clamp may be part of the derailleur body or housing, or it may be separate from the housing. One drawback of clamps is their inability to accommodate a wide variety of bicycle frames, making it necessary to precisely match frames with clamps having corresponding diameters.
European Patent No. 1 040 991 A2 discloses an adapter for decreasing the clamping diameter of a front derailleur clamp to conform to the diameter of a bicycle frame tube. This adapter generally includes two insert parts, each having a plastic fastening frame and a metal spacing element. The clamp includes two arms pivotally coupled together and fastening frames secured to the arms. The spacing element has an inner surface corresponding to the diameter of the frame tube, and a wall thickness that occupies the space between the clamp and the frame tube. In order to adapt the clamp for a different frame tube diameter, two new spacing elements—with corresponding new diameters—are required. The two new spacing elements must then be inserted into the fastening frames arranged on the arms of the clamping device. One disadvantage of this adapter is that it includes four pieces—two plastic frames and two aluminum spacing elements—resulting in costly production and time-consuming installation. Accordingly, there is a need for a one-piece clamping insert that is simple to install.